(1) Field of the Invention
This invention relates to antenna assemblies and is directed more particularly to an assembly including means for moving the antenna along its axis and rotatively about its axis.
(2) Description of the Prior Art
Submarine radar antenna operating mechanisms are located within and protrude through the top of the bridge access trunk of the submarine. The mechanisms, as presently constituted, require space which, in turn, requires an enlarged access trunk structure which adds considerable weight to the sail area of the submarine, well above the center of gravity of the boat.
The mechanism, as presently constituted, includes a large and heavy motor and reduction gear assembly for inside the bridge access trunk. For raising and lowering of the antenna, there is a hydraulic actuator inside the sail, which is outside the pressure hull. On several occasions, leakage of hydraulic fluid in the hydraulic raising and lowering system has led to gradual raising of the antenna, or "creep" which has caused the antenna to extend into the underwater environment, causing the antenna to be torn from its foundation during submerged submarine maneuvers. The location of the hydraulic mechanism for raising and lowering the antenna requires that hydraulic fluid be supplied to the sail area.
There is a need for a relatively light weight antenna assembly requiring less space and therefore less structural weight in the sail area of a submarine. There is further a need for such an assembly as does not require a supply of hydraulic fluid to the sail area and is not subject to "creep". There is also a need for a non-hull-penetrating mast, in order to divorce the antenna position in the sail from the hull arrangement.